Management of gag reflex for patients undergoing dental treatment

The gag reflex is an involuntary defence mechanism to protect the pharynx and throat from foreign objects. Gagging is a common problem encountered during dental treatment, making therapeutic procedures distressing and often difficult or even impossible to perform. Various interventions can be used to control the gag reflex: anti-nausea medicines, sedatives, local and general anaesthetics, herbal remedies, behavioural therapies, acupressure, acupuncture, laser, and prosthetic devices. This is an update of the Cochrane Review first published in 2015.

To assess the effects of pharmacological and non-pharmacological interventions for the management of gagging in people undergoing dental treatment.

Cochrane Oral Health's Information Specialist searched the Cochrane Oral Health's Trials Register (to 18 March 2019), the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 2) in the Cochrane Library (searched 18 March 2019), MEDLINE Ovid (1946 to 18 March 2019), Embase Ovid (1980 to 18 March 2019), CINAHL EBSCO (1937 to 18 March 2019), AMED Ovid (1985 to 18 March 2019), and the proceedings of the International Association for Dental Research (IADR) online (2001 to 18 March 2019). The US National Institutes of Health Ongoing Trials Register (ClinicalTrials.gov) and the World Health Organization International Clinical Trials Registry Platform were searched for ongoing trials. We also conducted forwards citation searching on the included studies via Google Scholar. No restrictions were placed on the language or date of publication when searching the electronic databases.

We included randomised controlled trials (RCTs), involving people who were given a pharmacological or non-pharmacological intervention to manage gagging that interfered with dental treatment. We excluded quasi-RCTs. We excluded trials with participants who had central or peripheral nervous system disorders, who had oral lesions or were on systemic medications that might affect the gag sensation, or had undergone surgery which might alter anatomy permanently.

We independently selected trials, extracted data, and assessed risk of bias. We followed Cochrane's statistical guidelines. We assessed the overall certainty of the evidence using GRADE.

We included four trials at unclear risk of bias with 328 participants (263 adults and 65 children who were four years or older), in which one trial compared acupuncture and acupressure (with thumb, device and sea band) at P6 (point located three-finger breadths below the wrist on the inner forearm in between the two tendons) to sham acupuncture and acupressure with and without sedation. One trial compared acupuncture at P6 point to sham acupuncture. These trials reported both completion of dental procedure and reduction in gagging (assessor and patient reported) as their outcomes. One cross-over and one split-mouth trial studied the effect of laser at P6 point compared to control. One trial reported reduction in gagging and another reported presence or absence of gagging during dental procedure. Acupuncture at P6 showed uncertain evidence regarding the successful completion of dental procedure (RR 1.78, 95% CI 1.05 to 3.01; two trials, 59 participants; very low-certainty evidence) and uncertain evidence regarding the reduction in gagging (RR 2.57, 95% CI 1.12 to 5.89; one trial, 26 participants; very low-certainty evidence) in comparison to sham acupuncture. Acupuncture at P6 with sedation did not show any difference when compared to sham acupuncture with sedation (RR 1.08, 95% CI 0.91 to 1.28; one trial, 34 participants; very low-certainty evidence). Acupressure using thumb pressure with or without sedation showed no clear difference in completing dental procedure (RR 0.96, 95% CI 0.84 to 1.10; one trial, 39 participants; very low-certainty evidence; and RR 0.85, 95% CI 0.50 to 1.46; one trial, 30 participants; very low-certainty evidence; respectively), or reduction in gagging (RR 1.06, 95% CI 0.92 to 1.23; one trial, 39 participants; very low-certainty evidence; and RR 0.92, 95% CI 0.60 to 1.41; one trial, 30 participants; very low-certainty evidence; respectively) when compared to sham acupressure with or without sedation. Acupressure at P6 with device showed uncertain evidence regarding the successful completion of dental procedure (RR 2.63, 95% CI 1.33 to 5.18; one trial, 34 participants; very low-certainty evidence) and uncertain evidence regarding the reduction in gagging (RR 3.94, 95% CI 1.63 to 9.53; one trial, 34 participants; very low-certainty evidence) when compared to sham acupressure. However, device combined with sedation showed no difference for either outcome (RR 1.16, 95% CI 0.90 to 1.48; one trial, 27 participants; very low-certainty evidence; and RR 1.26, 95% CI 0.93 to 1.69; one trial, 27 participants; very low-certainty evidence; respectively). Acupressure using a sea band with or without sedation showed no clear difference in completing dental procedure (RR 0.88, 95% CI 0.67 to 1.17; one trial, 21 participants; very low-certainty evidence; and RR 1.80, 95% CI 0.63 to 5.16; one trial, 19 participants; very low-certainty evidence; respectively), or reduction in gagging (RR 0.88, 95% CI 0.67 to 1.17; one trial, 21 participants; very low-certainty evidence; and RR 2.70, 95% CI 0.72 to 10.14; one trial, 19 participants; very low-certainty evidence; respectively) when compared to sham acupressure with or without sedation. Laser at P6 showed a difference in absence of gagging (odds ratio (OR) 86.33, 95% CI 29.41 to 253.45; one trial, 40 participants; very low-certainty evidence) and reduction in gagging (MD 1.80, 95% CI 1.53 to 2.07; one trial, 25 participants; very low-certainty evidence) during dental procedure when compared to dummy laser application. No noteworthy adverse effects were reported. For acupuncture at P6, the trial authors were unsure whether the reported adverse effects were due to participant anxiety or due to the intervention. None of the trials on acupressure or laser reported on this outcome. We did not find trials evaluating any other interventions used to manage gagging in people undergoing dental treatment.

We found very low-certainty evidence from four trials that was insufficient to conclude if there is any benefit of acupuncture, acupressure or laser at P6 point in reducing gagging and allowing successful completion of dental procedures. We did not find any evidence on any other interventions for managing the gag reflex during dental treatment. More well-designed and well-reported trials evaluating different interventions are needed.